This invention relates to ultrasonic transducer arrays and especially to a method of making a front surface matched array including electrical connections to the fully independent transducer elements.
A transducer array with high sensitivity and short impulse response for use in electronically steered beam imagers to make wide angle sector scans has a large number of piezoelectric ceramic elements and one or more quarter wavelength impedance matching layers on the front surface of each element. The matching layers as well as the ceramic are completely cut through so that the elements are supported on their ends and held together at the front by a continuous thin layer of tape and wear plate. This array configuration is disclosed and claimed in copending application Ser. No. 958,654, and the wear plate in application Ser. No. 958,655, both filed on Nov. 8, 1978 by the instant inventors and assigned to the same assignee as this invention.
Manufacturing the fragile front surface matched array, assembling it into a transducer head with sufficient mechanical strength for medical diagnostic examination or water tank testing, and making electrical connections to every individual element are not trivial problems. The piezoelectric elements are spaced on a grid with centers at sub-millimeter distances, and it is necessary to make separate signal lead and ground connections to the fully independent elements.